This project assesses methods for decreasing HIV-risk behaviors in substance abusers, and assesses the safety and efficacy of pharmacological and behavioral treatments for opioid dependence in those already infected with HIV. We have previously shown that methadone maintenance has broad beneficial effects of reducing HIV risk behaviors, with limited additional benefit from CBT for reduction of sexual risk behaviors when augmented with behavioral interventions.[unreadable] In the past year we examined the relationship between HIV-risk behaviors and infection with hepatitis C. Data showed that approximately one half of participants in a treatment research project for dual heroin/cocaine users were infected with hepatitis C. Those infected with hepatitis C were more likely to report engaging in HIV-risk behaviors, especially those related to injection drug use, prior to treatment entry. During treatment, hepatis C-positive participants reported decreased rates of HIV-risk behaviors. Infection with hepatitis C did not affect rate of adverse medical events during treatment. We are continuing to explore the relationship between HIV risk and hepatitis C infection and prevention.